Tolerance compensation in a reusable clamp structure

Abstract

A clamp structure with a clamping band which can be used, for example, to fixedly secure a hose on a nipple and which includes a tightening arrangement for tightening the clamp structure about the object to be fastened and a tolerance-compensating arrangement for the entire tolerance range of the hose and nipple. The tolerance-compensating arrangement is thereby formed by a slot-like opening punched-out of the clamping band which is of such width and length that the lateral clamping band portions left on both sides of the slot-like opening provide tolerance compensation at the clamping forces specified by the customer, taking into consideration also the fact that the material of the lateral band portions is work-hardened by the punching-out operation of the tolerance-compensating opening.

I claim: 
     
       1. A method for providing tolerance compensation in a clamping band made from metal having low elastic stretchability in the longitudinal direction under tensional tightening stresses, comprising the steps of: (a) preparing a sample of the clamping band with an opening punched-out in a central area, which work-hardens the remaining lateral band portions surrounding the opening,   (b) determining the yield strength and ultimate strength of the work-hardened lateral band portions,   (c) determining the elongation of the sample corresponding to said yield strength and said ultimate strength in terms of percentage elongation, and   (d) calculating the necessary length of the opening in the longitudinal direction as a function of the determined elongation percentages to provide a given tolerance compensation in the clamping band in the presence of tensional forces when the clamping band is in a fully tightened state.   
     
     
       2. A method according to claim 1, further comprising the step of making a clamp structure by utilizing a determined tolerance-compensating opening of width and length providing the tolerance compensation as calculated and capable of withstanding the maximum clamping forces expected in the clamp structure. 
     
     
       3. A method for imparting elastic stretchability to a full-width clamping band of a clamp structure to compensate for tolerance in the diametric dimension of an object to be fastened thereby, whereby the clamping band is made from a material having relatively low elastic stretchability in the longitudinal direction of the clamping band, and whereby the clamp structure is an open clamp structure having overlapping band portions adapted to be mechanically interconnected to provide a predetermined clamp structure corresponding substantially to the minimum diameter of the object to be fastened thereby when the clamp structure is installed, said method comprising: determining the yield strength and ultimate strength of the clamping band,   determining the elongation of the clamping band corresponding to said yield strength and said ultimate strength, and   stamping an elongated opening out of the clamping band of such length and width that the remaining portions of the clamping band surrounding the elongated opening can withstand a predetermined tensile load and provide an elongation in the clamping band sufficient to accommodate an expected tolerance range in the outside diametric dimension of the object to be fastened thereby prior to reaching the yield strength of the material from which the clamping band is made, wherein the length of the elongated opening is calculated as a function of the determined elongation percentages to provide a given tolerance compensation in the presence of tensional forces in the clamping band in a fully tightened state, thereby rendering the clamping band capable of withstanding the maximum clamping force expected in the clamp structure.     
     
     
       4. A method according to claim 3, wherein the stamping step work-hardens the adjacent areas of the clamping band surrounding the opening, and further comprising the step of determining the width and length of the opening on the basis of the cross-section of the work-hardened areas by taking into consideration the yield strength of the work-hardened clamping band material, the maximum tensional stresses expected in the clamping band and the necessary elongation to provide tolerance compensation prior to reaching said yield strength. 
     
     
       5. A method according to claim 3, wherein the elongated opening is stamped out exclusively within the area of the clamping band and has a width narrower than the normal width of the clamping band.